Abstract: Post-weld plastic deformation can improve the joint residual stress distribution and joint toughness. By comparing the law of CGHAZ tissue form, grain size and orientation, stress distribution, toughness and fracture morphology of X80 steel in welding, post-welding at 450 ℃ and 650 ℃ states, the influence of post-welding rolling on improving the organizational performance of steel joints of X80 pipeline was explored. The experimental results show that: with the post-weld milling, the number of acicular ferrite in the CGHAZ area gradually increases, and the shape is irregular. The grains are subjected to some deformation as well as the uniformity of the grains is improved. Post-weld milling can refine the grain size to a certain extent, with the increase of the post-weld milling temperature, the average value of the local orientation difference of the grains in the CGHAZ is gradually increased, the content of the small-angle grain boundaries is gradually decreasing, and the content of the large-angle grain boundaries is gradually increasing. After post-weld milling, the impact toughness of the welded joints is reduced, the stress distribution and fracture morphology are improved. The impact toughness of the welded joints is improved by post-welding milling, and the density of the toughness nests on the fracture is increased,which is an obvious toughness fracture. Post-welding milling can reduce the residual stress, and make the residual tensile stress become residual compressive stress, which can improve the distribution of residual stresses in the joint.